Integrated circuit placement system

ABSTRACT

This invention relates to a dice placement assembly for placing dice on a carrier. The assembly includes a support platform with a clamp mechanism configured to clamp the carrier onto said platform, and at least one camera operatively directed at the platform to detect alignment fiducials on the carrier. The assembly also includes a placement device having a vacuum mechanism to retrieve the dice from a supply mechanism, said placement device having actuators to align the dice with the carrier and to place the dice thereon once aligned, and a heater to heat the dice prior to placement on the test bed. Further included is a controller operatively controlling the clamp mechanism, the camera and the placement device, to facilitate accurate placement of the dice on the carrier.

FIELD OF INVENTION

The invention relates to the assembly of printhead integrated circuitcomponents. More specifically, the invention provides for an assemblerand associated methods of assembling printhead integrated circuits on acarrier.

CO-PENDING APPLICATIONS

The following applications have been filed by the Applicantsimultaneously with the present application:

12,193,715 12,193,716 12,193,717 12,193,718 12,193,719 12,193,7207,804,292 7,786,723 12,193,723 12,193,724 12,193,725 7,789,47712,193,727 12,193,728 12,193,729 12,193,730 12,193,731 12,193,73212,193,733 12,193,734 12,193,735 12,193,736 7,721,420 12,193,73812,193,739 12,193,740 12,193,741 7,805,832 12,193,743 12,193,74712,193,748 12,193,750 12,193,751 12,193,753

The disclosures of these co-pending applications are incorporated hereinby reference.

CROSS REFERENCES

The following patents or patent applications filed by the applicant orassignee of the present invention are hereby incorporated bycross-reference.

11/246,687 11/246,718  7,322,681 11/246,686 11/246,703 11/246,69111/246,711 11/246,690 11/246,712 11/246,717  7,401,890  7,401,91011/246,701 11/246,702 11/246,668 11/246,697 11/246,698 11/246,69911/246,675 11/246,674 11/246,667 11/829,957 11/829,960 11/829,96111/829,962 11/829,963 11/829,966 11/829,967 11/829,968 11/829,96911,946,839 11,946,838 11,946,837 11,951,230 12,141,034 12,140,26512,183,003 11/688,863 11/688,864 11/688,865  7,364,265 11/688,86711/688,868 11/688,869 11/688,871 11/688,872 11/688,873 11/741,76612,014,767 12,014,768 12,014,769 12,014,770 12,014,771 12,014,77212,014,773 12,014,774 12,014,775 12,014,776 12,014,777 12,014,77812,014,779 12,014,780 12,014,781 12,014,782 12,014,783 12,014,78412,014,785 12,014,787 12,014,788 12,014,789 12,014,790 12,014,79112,014,792 12,014,793 12,014,794 12,014,796 12,014,798 12,014,80112,014,803 12,014,804 12,014,805 12,014,806 12,014,807 12,049,37112,049,372 12,049,373 12,049,374 12,049,375 12,103,674 12,146,399

BACKGROUND

Pagewidth printers that incorporate micro-electromechanical componentsgenerally have printhead integrated circuits that include a siliconsubstrate with a large number of densely arrangedmicro-electromechanical nozzle arrangements. Each nozzle arrangement isresponsible for ejecting a stream of ink drops.

In order for such printers to print accurately and maintain quality, itis important that the printhead integrated circuits be tested. This isparticularly important during the design and development of suchintegrated circuits.

Some form of carrier is generally required for testing such integratedcircuits.

SUMMARY

According to a first aspect of the invention, there is provided anassembler for assembling printhead dice on a carrier, the assemblercomprising

-   -   a support assembly;    -   a wafer positioning assembly arranged on the support assembly        and configured to retain and position a wafer containing        printhead dice to be picked from the wafer;    -   a dice picking assembly arranged on the support assembly and        configured to pick a pre-selected dice from the wafer;    -   a dice placement assembly arranged on the support assembly and        configured to receive the pre-selected dice and to place the        dice on the carrier;    -   a dice conveyance mechanism arranged on the support assembly and        configured to convey the dice from the dice picking assembly to        the dice placement assembly; and    -   a control system operatively engaged with the wafer positioning,        dice picking, dice placement and dice conveyance assemblies to        control operation thereof.

The support assembly may include an optical table and a block mountingmember positioned on the optical table, the wafer positioning assemblybeing positioned on the block mounting member and the support assemblybeing configured to support the dice picking assembly above the waferpositioning assembly.

The wafer positioning assembly may include a base member mounted on theblock and first and second stages mounted on the base member, the firststage interposed between the base member and the second stage and beingdisplaceable relative to the base member along a first linear axis, thesecond stage being displaceable relative to the first stage along asecond linear axis orthogonal to the first linear axis, and a wafersupport assembly positioned on the second stage for rotation about arotational axis orthogonal to both the first and second linear axes, thewafer support assembly being configured to support the wafer.

The dice picking assembly may include a carrier assembly fast with thesupport assembly and displaceable relative to the support assemblytowards and away from the wafer positioning assembly, a dice pick andlift head being positioned on the carrier assembly and configured toengage the pre-selected dice when the carrier assembly is in a loweredposition and to release said pre-selected dice when the carrier assemblyis in a raised position.

The dice conveyance mechanism may include a gantry assembly positionedon the support assembly and having a gantry member that spans the waferassembly, a shuttle assembly configured to receive and support thepre-selected dice being mounted on the gantry member and beingdisplaceable relative thereto between a receiving position to receivethe dice released by the dice picking assembly and a delivery positionin which the dice are delivered to the placement assembly.

According to a second aspect of the invention, there is provided atransfer apparatus for transferring a component of integrated circuitryfrom a receiving location to a delivery location within an integratedcircuitry assembly machine, the transfer apparatus comprising

-   -   a support structure that defines a transfer path between said        locations;    -   a component carrier that defines a receiving zone configured to        receive the component of integrated circuitry;    -   a retaining mechanism arranged on the component carrier to        retain the component of integrated circuitry in position in the        receiving zone, the retaining mechanism being operable to        release the component at the delivery location; and    -   a displacement mechanism engaged with the component carrier to        displace the component carrier along said transfer path.

The support structure may include a support arm extending between saidreceiving and delivery locations such that the transfer path is linear,the displacement mechanism including a linear motor arranged on thesupport arm.

The component carrier may include a shuttle plate, the receiving zonebeing defined by a vacuum plate arranged on the shuttle plate, theretaining mechanism including a gel pack for retaining the component ofintegrated circuitry.

The component carrier may include a vacuum tube arranged in fluidcommunication with the vacuum plate, said tube arranged in fluidcommunication with a vacuum pump operable to draw air through aperturesdefined in the vacuum plate to operatively retain the component ofintegrated circuitry to said vacuum plate.

The displacement mechanism may include a linear motor positioned on thesupport structure, said linear motor configured to displace thecomponent carrier along the transfer path.

According to a third aspect of the invention, there is provided a diepicker for picking printhead integrated circuitry from a wafer, saidpicker comprising:

-   -   a wafer platform having a displacement actuator to displace said        platform which operatively receives the wafer;    -   a picker head having a vacuum mechanism to lift a dice of the        circuitry from said wafer;    -   an alignment sensor configured to detect a position of the dice        on the wafer; and    -   a controller arranged in control signal communication with the        displacement actuator, the picker head and the sensor to        facilitate aligning the wafer with the picker head, and to pick        the dice from the wafer with the head for transport to a        transfer apparatus.

The displacement actuator may include two piezo motor stages attached tothe platform to move the platform in a plane below the picker head. Thedisplacement actuator may include a rotary axis motor configured torotate the wafer platform below the picker head.

The wafer platform may include a heater plate configured to heat thewafer to soften an adhesive holding the dice to the wafer, with a vacuumplate to retain said wafer to the platform. The alignment sensor mayinclude a camera with a lens adapter and prism to focus on identifyingindicia on said wafer to facilitate the controller aligning the pickerhead with the dice.

The controller may operatively execute a set of instructions accordingto a predetermined wafer substrate mapping scheme to align the waferwith the picker head. The picker head may include a heater element toheat the dice to soften an adhesive holding the dice to the wafer priorto lifting said dice from the wafer.

According to a fourth aspect of the invention, there is provided a diceplacement assembly for placing an integrated circuit dice on a carrier,said assembly comprising:

-   -   a support platform with a clamp mechanism configured to clamp        the carrier onto said platform;    -   at least one camera operatively directed at the platform to        detect alignment fiducials on the carrier;    -   a placement device having a vacuum mechanism to retrieve the        dice from a supply mechanism, said placement device having        actuators to align the dice with the carrier and to place the        dice thereon once aligned, and a heater to heat the dice prior        to placement on the carrier; and    -   a controller operatively controlling the clamp mechanism, the        camera and the placement device, to facilitate accurate        placement of the dice on the carrier.    -   Preferably, the integrated circuit dice are inkjet printhead        dice.

The camera may include a camera module linked to a prism by means of anadapter tube to focus said camera on the test bed. The support platformmay include a pneumatically operated self-leveling platform controlledby the controller.

The actuators of the placement device may include three stepper motorseach separately responsible for vertical, horizontal and angularalignment of the dice with the test bed, respectively. The actuators ofthe placement device may include a linear translation stage for movingthe dice in a vertical direction for placing the dice onto the test bed.

The placement device may include a heated air blower configured todirect heated air at the dice prior to the placement device placing thedice onto the test bed. The placement device may include a lightingarrangement for illuminating the test bed to assist the camera indetecting the alignment fiducials.

According to a fifth aspect of the invention, there is provided a methodof attaching integrated circuit dice to a carrier, said methodcomprising:

-   -   scanning a wafer having a number of circuitry dice formed        thereon to demarcate respective dice;    -   aligning a die picker with a dice on the wafer according to a        wafer substrate mapping scheme;    -   removing the dice from the wafer with the die picker;    -   transporting the dice to a placement station operatively        positioning the carrier;    -   aligning the dice with the carrier; and    -   heat bonding the dice to the carrier.

Preferably, the integrated circuit dice are inkjet printhead dice.

Preferably, the step of scanning includes scanning the wafer with acamera arrangement to identify fiducial marks on the wafer.

Preferably, the step of removing the dice includes heating the wafer andapplying a vacuum to the respective dice targeted for removal with thedie picker.

Preferably, the step of transporting the dice includes depositing thedice onto a shuttle assembly of an assembler displaceable between areceiving position where the dice is received and a delivery position inwhich the dice is delivered to a placement assembly.

Preferably, the step of aligning the dice with the carrier includesscanning the dice and the carrier with a camera arrangement to identifyfiducial markings on both said dice and carrier, and displacing the dicerelative to the carrier until the fiducial markings on the dice is in apredetermined position relative to the fiducial markings of the carrier.

Preferably, the step of identifying the fiducial markings includesexamining the carrier with a camera having a focusing lens arrangementto identify microscopic apertures in a surface of the carrier, saidapertures identified as the fiducial markings.

Preferably, the respective steps are performed by a controller of anassembler having a wafer positioning assembly, a dice picking assembly,a dice conveyance mechanism, and a dice placement assembly forimplementing such steps according to a set of instructions included in asoftware product.

According to a sixth aspect of the invention, there is provided a waferpositioning assembly for an assembler for assembling integrated circuitdice on a carrier, said assembler having an enclosure with a supportassembly for operatively supporting a wafer with dice thereon, a diepicking assembly for picking dice from said wafer, a die placementassembly for placing the dice onto the carrier, a die conveyancemechanism operatively conveying the dice from the die picking andplacement assemblies, and a control system controlling the assembler,said wafer positioning assembly comprising:

-   -   a displacement assembly having a base plate with first and        second stages mounted thereon; and    -   a wafer support plate assembly rotatably mounted on the second        stage, the support plate assembly configured to receive the        wafer and having a motor under control of the control system to        rotate the support plate assembly underneath the die picking        assembly.

Preferably, the integrated circuit dice are inkjet printhead dice.

Preferably, the first stage is interposed between the base plate and thesecond stage, the first stage slidably mounted on the base plate along afirst axis, the second stage slidably mounted on the first stage along asecond axis perpendicular to the first axis.

Preferably, the assembly has a first piezo motor interconnecting thebase plate and the first stage, said first motor under control of thecontrol system to displace the first stage along the first axis.

Preferably, the assembly has a second piezo motor interconnecting thefirst stage and the second stage, said second motor under control of thecontrol system to displace the second stage along the second axis.

Preferably, the wafer support plate assembly includes a bearing tablerotatably mounted to the second stage, the wafer support plate assemblyhaving a bearing retainer sandwiched between the second stage and saidbearing table to ensure smooth rotation of the wafer support plateassembly on the second stage.

Preferably, the wafer support plate assembly includes a rotating pinwith a compression spring about said pin, the compression springprovides dampening for vertical movement of the wafer support plateassembly on the second stage.

Preferably, a heater plate is mounted on the bearing table with spacersto provide thermal isolation between the heater plate and bearing table,a vacuum plate mounted on, and fast with, the heater plate.

Preferably, both the vacuum plate and the heater plate define a numberof vacuum apertures, vacuum tubes being connected to an underside of theheater plate in fluid communication with the vacuum apertures, the tubesconnected to a vacuum manifold connected to a vacuum pump of theassembler, operation of the vacuum pump retaining the wafer to thevacuum plate.

Preferably, a heater cartridge is interposed between the vacuum plateand the heater plate, said heater cartridge connected to a heated airsupply of the assembler so that the heater plate is able to heat thewafer.

Preferably, a stepper motor assembly is mounted on the second stage, apower screw of the stepper motor assembly extending from the steppermotor to engage the wafer support plate assembly in a tangential manner.

Preferably, a working end of the power screw is fast with a connectorarm extending from the bearing table, so that extension and retractionof the power screw causes the wafer support plate assembly to rotateanti-clockwise and clockwise, respectively.

According to a seventh aspect of the invention, there is provided a dicepick and lift head for an assembler for assembling integrated circuitdice on a carrier, said assembler having an enclosure with a supportassembly for operatively supporting a wafer with dice thereon, a diepicking assembly for picking dice from said wafer, a die placementassembly for placing the dice onto the carrier, a die conveyancemechanism operatively conveying the dice from the die picking andplacement assemblies, and a control system controlling the assembler,said dice pick and lift head comprising:

-   -   a first translation stage mounted to the die picking assembly,        said first translation stage operatively displaceable along a        vertical axis relative to the support assembly;    -   a second translation stage mounted to the first translation        stage, said second translation stage operatively displaceable        along a horizontal axis relative to the support assembly; and

a die picker head mounted to the second translation stage, the pickerhead defining a vacuum chamber and a dice contact surface having vacuumapertures in fluid communication with the vacuum chamber.

Preferably, the integrated circuit dice are inkjet printhead dice.

Preferably, the first translation stage includes a stepper motor undercontrol of the control system, the motor having a linear encoder toprovide positional feed back values of the picker head to the controlsystem.

Preferably, the linear encoder is arranged proximate scale tape fastwith the die picking assembly to facilitate the linear encodergenerating the positional feed back values.

Preferably, the second translation stage includes a pair of micrometerdrives fast with the first stage to displace the pick head thehorizontal axis, said drives under control of the control system.

Preferably, the die picker head includes a pair of sealing stripspositioned on respective sides of the vacuum apertures on the dicecontact surface to facilitate the generation of a vacuum between a diceto be lifted and the dice contact surface.

Preferably, the dice pick and lift head has a vacuum tube fast with thevacuum body, the tube connected to a vacuum pump under control of thecontrol system configured to generate a vacuum in the chamber when thecontact surface touches a dice.

Preferably, a heater cartridge is positioned in the vacuum body and isconnected to a heated air supply to heat the dice contact surface, athermocouple being connected to the contact surface to sense thetemperature thereof and report the sensed temperature to the controlsystem.

According to an eighth aspect of the invention, there is provided aplacement head for a die placing assembly of an assembler for assemblingintegrated circuit dice on a carrier, said assembler having an enclosurewith a support assembly for operatively supporting a wafer with dicethereon, a die picking assembly for picking dice from said wafer, a dieplacement assembly for placing the dice onto the carrier, a dieconveyance mechanism operatively conveying the dice from the die pickingand placement assemblies, and a control system controlling theassembler, said placement head comprising:

-   -   a first translation stage mounted on the die placement assembly,        said first stage operatively displaceable along a first axis        relative to the die placement assembly;    -   a second translation stage mounted on the first stage, the        second stage displaceable perpendicular to the first stage;    -   a third translation stage mounted on the second stage, the third        stage displaceable orthogonally to the first and second stages;        and    -   a die placer head mounted to the third stage, the placer head        shaped and dimensioned to operatively receive a die from the        dice conveyance mechanism and to place the dice onto the        carrier.

Preferably, said integrated circuit dice are inkjet printhead dice.

Preferably the placement head has an angular motor mounted through thethird stage in contact with the die placer head, so that actuation ofthe angular motor by the control system causes angular pivoting of thedie placer head about an axis in which the second stage translates.

Preferably the placement head has an angular movement spring fast withthe third stage, the spring configured to bias the placer againstangular movement provided by the angular motor.

Preferably the placement head has a placement head mounting blockassembly which includes a mounting plate, said placement head fast withan upright portion of a frame of the die placing assembly via saidmounting plate.

Preferably the placement head has a first stage stepper motor fast withthe block assembly via a bracket assembly, the first stage stepper motorhaving a pushrod that operatively engages the first stage to push thefirst stage along a first axis with respect to the block assembly.

Preferably the placement head has a second stage stepper motor fast withthe first stage via a bracket assembly, a push bracket fast with thesecond stage and engaging a pushrod of the second stage stepper motorvia a compression spring, a linear encoder mounted on the first stagewith scale tape fast with the second stage to be read by said linearencoder to provide positional feedback along the second axis to thecontrol system.

Preferably the placement head has a pair of third stage micrometerdrives mounted on the second stage and engaged with the third stage toprovide adjustment of the third stage, said micrometer drives undercontrol of the control system.

Preferably, the die placer head defines an aperture in fluidcommunication with a vacuum tube connected to a vacuum pump of theassembler, the aperture shaped and dimensioned to receive a die from thewafer, the die operatively held in the aperture by said vacuum pump.

According to a ninth aspect of the invention, there is provided clampassembly for an assembler for assembling printhead integrated circuitryon a carrier, said assembler having an enclosure with a support assemblyfor operatively supporting a wafer with dies thereon, a die pickingassembly for picking dice from said wafer, a die placement assembly forplacing the dies onto the carrier, a die conveyance mechanismoperatively conveying the dies from the die picking and placementassemblies, and a control system controlling the assembler, said clampassembly comprising:

-   -   an elongate clamp body, the body shaped and configured to be        received by the die placement assembly;

a pair of elongate retaining plates mounted on top of the body;

-   -   an insert shaped and dimensioned to be received in the body        below the plates, the insert operatively receiving said carrier;        and    -   a diaphragm positioned in the body, the diaphragm pneumatically        displaceable to operatively urge the insert against the        retaining plates.

The insert may include a number of locating dowels for complementarilyengaging associated apertures defined in the carrier to ensure that thecarrier is correctly positioned.

The insert may be slidably receivable in the body, said body includingan insert stop at one end thereof with a proximity switch mounted on thestop and configured to generate a signal for the control system when theinsert reaches the stop.

The plates may be mounted on the body to define an access gap ofsufficient width to permit positioning of the printhead integratedcircuitry on the carrier via said gap.

The body may include a pneumatic fitting and define pneumatic chamber tofacilitate pneumatic actuation of the diaphragm via a pneumatic systemof the assembler.

The clamp assembly may include a handle fast with the insert tofacilitate manipulation of the carrier into position between the clampplates.

According to an tenth aspect of the invention there is provided asoftware product for execution by a processor, said software producthaving instructions configured to enable the processor to perform thesteps of the above method.

According to an eleventh aspect of the invention there is provided acomputer readable medium operatively storing a software product forexecution by a processor, said software product having instructionsconfigured to enable the processor to perform the steps of the abovemethod.

BRIEF DESCRIPTION OF THE DRAWINGS

Preferred features, embodiments and variations of the invention may bediscerned from the following Detailed Description which providessufficient information for those skilled in the art to perform theinvention. The Detailed Description is not to be regarded as limitingthe scope of the preceding Summary of the Invention in any way. TheDetailed Description will make reference to a number of drawings asfollows:

FIG. 1 shows an example of a wafer that defined a plurality of printheadintegrated circuits (ICs) or dice;

FIG. 2 shows a perspective view of a carrier or test bed on which theprinthead integrated circuits (ICs) are to be placed or assembled;

FIG. 3 shows a perspective view of one embodiment of an assembler forassembling the ICs on the carrier;

FIG. 4 shows a perspective view of a dice picking assembly or dicepicker, in accordance with one embodiment of the invention, for pickingICs from the wafer;

FIG. 5 shows a wafer positioning assembly, in accordance with oneembodiment of the invention, of the picker of FIG. 4;

FIG. 6 shows a side sectioned view of the wafer positioning assemblyshown in FIG. 5;

FIG. 7 shows an underside view of the wafer positioning assembly shownin FIG. 5;

FIG. 8 shows a perspective view of a dice pick and lift head, inaccordance with one embodiment of the invention, of FIG. 4;

FIG. 9 shows a further perspective view of the dice pick and lift headshown in FIG. 8;

FIG. 10 shows a further perspective view of the die pick and lift headshown in FIG. 8;

FIG. 11 shows a close-up view of part of a die picker of the pick andlift head shown as “A” in FIG. 10;

FIG. 12 shows an embodiment of a camera arrangement of the die pickingassembly of FIG. 4;

FIG. 13 shows a perspective view of a wafer scribe reader of the diepicking assembly of FIG. 4;

FIG. 14 shows a perspective view of a transfer apparatus, in accordancewith one embodiment of the invention, in the form of a dice conveyanceassembly of the assembler of FIG. 3;

FIG. 15 shows a closer view of a component carrier or shuttle of thedice conveyance assembly of FIG. 14;

FIG. 16 shows a dice placement assembly, in accordance with oneembodiment of the invention, of the dice assembler of FIG. 3, theplacement assembly in a carrier loading position;

FIG. 17 shows the dice placement assembly of FIG. 16 in a dice placingposition;

FIG. 18 shows a perspective view of a dice placement head, in accordancewith one embodiment of the invention, of the dice placement assembly ofFIG. 16;

FIG. 19 shows a further perspective view of a dice placement head of thedice placement assembly of FIG. 16;

FIG. 20 shows an air heater assembly, in accordance with one embodimentof the invention, of the dice placement assembly of FIG. 16;

FIG. 21 shows a perspective view of a clamp mechanism used to positionthe test bed or carrier of FIG. 2 in the assembler;

FIG. 22 shows a side sectional view of the clamp mechanism of FIG. 21;

FIG. 23 shows a schematic diagram of high level data flow used tocontrol the assembler of FIG. 3;

FIG. 24 shows a diagram of high level method steps of using theassembler of FIG. 3 to assemble printhead circuitry on the carrier ofFIG. 2;

FIG. 25 shows a block diagram representing method steps for picking adie from a wafer;

FIG. 26 shows a block diagram representing method steps for transferringa dice between the die picking assembly and the die placement assembly;

FIG. 27 shows a block diagram representing method steps for placing adice onto the carrier of FIG. 2;

FIG. 28 shows an embodiment of an operator interface for the assemblerof FIG. 3;

FIG. 29 shows an electrical enclosure of the assembler in an openposition showing internal electrical components;

FIG. 30 shows a pneumatic enclosure of the assembler in an open positionshowing pneumatic components;

FIG. 31 shows a schematic diagram illustrating interaction of electricalcomponents used for motor control of the assembler of FIG. 3;

FIG. 32 shows a circuit diagram of a touch panel PC and opticalcomponents of the assembler;

FIG. 33 shows a circuit diagram of an LED controller of the assembler;

FIG. 34 shows a circuit diagram of a layout of a main controller of theassembler;

FIG. 35 shows a circuit diagram of a main safety relay of the assembler;

FIG. 36 shows a circuit diagram for an embodiment of a safety system ofthe assembler; and

FIGS. 37A and 37B show a circuit diagram of temperature controlcircuitry of the assembler.

DETAILED DESCRIPTION

Aspects of the invention are described below with reference to specificembodiments thereof. Reference to “an embodiment” or “one embodiment” ismade in an inclusive rather than restrictive sense. As such, referenceto particular features found in one embodiment does not exclude thosefeatures from other embodiments.

The following description is intended to assist a person skilled in theart with understanding the invention. Accordingly, features commonplacein the art are not described in particular detail, as such features willbe readily understood by the skilled person.

Overview

In broad terms, the invention relates to the assembly of printheadintegrated circuitry on a test bed or carrier. The assembly typicallycomprises removing dice from a wafer and placing said dice onto thecarrier or test bed with a high degree of accuracy.

The printhead integrated circuitry includes a series of printheadintegrated circuits (ICs) which have a plurality ofmicro-electromechanical nozzle arrangements that eject microdots of inkonto a printing surface. The ICs define a number of microscopic inkinlets which lead to respective nozzles, said inlets arranged in fluidcommunication with an ink distribution assembly. The ink distributionassembly is responsible for feeding ink to the ICs. An example of awafer 6 is shown in FIG. 1. As shown, the wafer 6 includes a pluralityof printhead ICs or dice 8 thereon. The wafer 6 is a product of variousetching and lithography processes common in IC manufacturing.

In order to test a printhead IC, each IC is mounted to the carrier,which defines a number of tortuous ink paths therein to form such an inkdistribution assembly. The ink paths terminate as microscopic inkoutlets in a surface of the carrier. Given the microscopic sizes of theink inlets of the ICs and the ink outlets, accurate and precisealignment of the ICs with the carrier is vitally important. Theinvention provides for an assembler and related apparatus and techniquesused to accurately fasten the ICs to the carrier.

Carrier 10

FIG. 2 shows an embodiment of such a carrier 10. It is to be appreciatedthat the terms carrier, test bed, base assembly, carrier sub-assembly,liquid crystal polymer (LCP) assembly, or platform substructure 10referred to herein all make reference to the same element indicated byreference numeral 10. The carrier 10 is generally an assembly of twoliquid crystal polymer (LCP) micro-moldings 11 a and 11 b. Themicro-moldings 11 define a plurality of discrete tortuous ink paths forducting ink from an ink reservoir (not shown) to printhead integratedcircuitry (not shown).

Accordingly, the carrier or test bed 10 is used to test the operation ofprototyped of such printhead integrated circuitry (IC) prior to massproduction of the ICs. Given the operation of these printhead ICs, it isgenerally necessary to establish a seal between the tortuous ink pathsdefined in the carrier 10 and fluid inlets of the ICs. For this reason,the Inventor has found that by laminating the carrier 10 with a laminafilm 12, such a fluid tight seal can be established between the carrier10 and IC when the IC is fastened to the carrier 10. This facilitatesfluid-tight supplying of ink to the printhead ICs.

The ink paths through the carrier 10 typically terminate as fiducialapertures or “fiducials” 14 in a surface of the carrier 10, shown inFIG. 1. It is therefore necessary to place the ICs on the carrier 10without blocking or impeding these fiducials 14, otherwise ink will beprevented from flowing through the carrier 10 to the printhead ICs.

The carrier 10 also defines two location openings 13 at respectiveopposite ends, as shown. The purpose of the location openings 13 is toaccurately fix and align the carrier 10 in a clamp prior to placing theICs thereon. Also included are carrier fiducials 15 to assist inaligning the carrier 10 prior to fastening the ICs thereon.

Overview of Assembler 16

In FIG. 3, there is shown an embodiment, in accordance with oneembodiment of the invention, of a printhead assembly machine orassembler 16. Physically, the printhead assembly machine 16 includes asupport assembly or structure 24 defining a main enclosure 25 having asupport frame 27 and side window panels 29, as shown. The side panels 29are typically transparent to allow an operator of the assembler 16 tosee inner workings thereof. Front panel 32 is indicated, withrepresentations of the inner components viewable therethrough, as shown.

The internal components of the assembler 16 includes a die pickingassembly or die picker 18, with wafer positioning assembly 17, inaccordance with one embodiment of the invention, a transfer apparatus ordie conveyance mechanism 20, in accordance with one embodiment of theinvention, and a die placement assembly 22, also in accordance with oneembodiment of the invention.

The support structure includes a self-leveling optical table 26supported by the support frame 27 in the enclosure 25. The dice pickingassembly 18 is mounted on the optical table 26 and is described indetail below. The dice picking assembly 18 is configured to pick dicefrom the wafer 6 loaded into the enclosure 25. The panels of theenclosure 25 are typically slidable to facilitate such loading of thewafer 6 and carrier 10. The dice placement assembly 22 is also mountedon the optical table 26 and is described in detail below. The dieplacement assembly 22 is configured to dice 8 on the carrier 10.

The dice conveyance mechanism or shuttle transfer assembly 20 isinterposed between the dice picking assembly 18 and the dice placementassembly 22. The dice conveyance mechanism 20 includes a gantry beam114, which is described in more detail below. The dice conveyancemechanism 20 is configured to receive a die from the dice pickingassembly 18 and to transfer said dice to the dice placement assembly 22.The dice conveyance mechanism 20 includes a transfer or shuttle gantry28 mounted on the optical table 26. The gantry 28 extends from the dicepicking assembly 18 to the dice placement assembly 22.

A touch panel PC 34 is mounted on the frame of the housing 24 and ispositioned to be accessed by an operator. A control panel 36 is alsomounted on the frame to be accessed by an operator. A light beacon 35 isalso mounted on the enclosure 24 to show an operating state of theassembler 16. Together, the touch panel PC 34 and the control panel 36constitute an operator interface whereby an operator can monitor andcontrol the working of the assembler 16. It is however to be appreciatedthat most of the assembler's functions are monitored and controlled by acontroller or control system, described below, which includes a PLC(programmable logic controller) 38. The operator interface allows anoperator to start and stop the assembler 16, with additional low-levelcontrol.

An ionizer bar 40 is positioned in the enclosure 24 together with a HEPAfan/filter arrangement 42 to achieve a suitable environment in theenclosure. An electrical enclosure 44 is mounted on the support frameand encloses the various electrical components for operation of theprinthead assembly machine 16, as described below. The housing 24 alsoincludes a pneumatic enclosure 46 which encloses the various pneumaticcomponents for operation of the machine 16, described in more detailbelow.

Die Picking Assembly 18

Referring now to FIG. 4, the purpose of the die picking assembly 18 isto select a die from the wafer 6, which is operatively secured to awafer support plate assembly 63, according to a predetermined pick listand to lift it and place the die in the shuttle transfer assembly 20.

The die picking assembly 18 includes a block mounting member 50 in theform of a block of granite mounted on the optical table 26. The block 50is typically rectangular, as shown. A wafer positioning assembly 48 ismounted on the block 50.

The wafer support plate assembly 63 enables the wafer 6 to be held inposition by means of a vacuum. A heater plate 71 is used to heat thewafer 6 under control of the PLC 38 via the thermocouple 79 to loosen anadhesive holding the dies or IC's 8 to the wafer, so that a dice pickand lift head 78 is able to pick a die from said wafer 6. A pick headgantry 80 is also mounted on the block 50.

As shown, the gantry 80 includes a pair of opposed gantry posts 810mounted on opposite corners of the block 50. The gantry 80 spans thewafer positioning assembly 18 and supports the die pick and lift head 78with a suitable bracket 87. The head 78 includes a pair of spaced wafercamera and optic assemblies 82. The assemblies 82 are connected to thePC 34 which is configured to receive image data representing the wafer 6and to control movement of the wafer support plate assembly 63, to alignsuccessive dies 8 with the head 78. Also included is wafer scribe reader100.

The respective assemblies are discussed in more detail below.

Wafer Positioning Assembly 48

The wafer positioning assembly 48, shown in more detail in FIG. 5,includes a base member or plate 52 mounted on the block 50. Adisplacement assembly 54 is mounted on the base plate 52. Thedisplacement assembly 54 includes two stages 56 and 58, with a firststage 56 interposed between the base plate 52 and a second stage 58.

The first stage 56 is displaceable relative to the base member 52 alonga first or U-axis. A first piezo motor 60 interconnects the base plate52 and the first stage 56. Thus, the first piezo motor 60 displaces thefirst and second stages along a V-axis with respect to the base plate52. The second stage 58 is displaceable relative to the first stage 56along a U-axis. A second piezo motor 62 interconnects the first andsecond stages. Thus, the second piezo motor 62 displaces the secondstage 58 along the U-axis with respect to the first stage 56.

The piezo motors 60 and 62 are connected to the PLC 38, with suitablecontrollers described below to control operation of the piezo motors.The PLC 38 and its manner of operation are described in more detailbelow.

Wafer Support Plate Assembly 63

The wafer support plate assembly 63 is rotatably mounted on the secondstage 58. The wafer support plate assembly 63 has a bearing table 69(FIG. 6) rotatably mounted on a base plate 64 on top of the second stage58. The wafer support plate assembly 63 includes a bearing retainer 65sandwiched between the plate 64 and the bearing table 69 to ensuresmooth rotation of the wafer support plate assembly 63. The wafersupport plate assembly 63 includes a rotating pin 67 with compressionspring 61 about which the wafer support plate assembly 63 can rotate onthe base plate 64. Compression spring 61 provides dampening of verticalmovement of the wafer support assembly 63.

The heater plate 71 is mounted on the bearing table 69, with spacers 75(FIG. 7) for thermal isolation. In turn, the bearing table 69 is mountedon the base plate 64. A vacuum plate 76 is mounted on, and fast with,the heater plate 71. Both the vacuum plate and the heater plate 76define a number of vacuum apertures 59. A number of vacuum tubes 57 areconnected to an underside of the heater plate 71 in fluid communicationwith the vacuum apertures 59, as shown. The tubes 57 are connected to avacuum manifold 55 connected to a vacuum pump 472 housed in thepneumatic enclosure 46, described below. Supply tubes 77 connect thevacuum pumps 472 with the manifold 55, as shown. Operation of the vacuumpumps 472 is controlled so that when a wafer is positioned on the vacuumplate 76, the wafer can be retained in position by a vacuum generated bythe vacuum pumps 472.

A heater cartridge 74 is interposed between the vacuum plate 76 and theheater plate 71. The heater cartridge 74 is connected to a heated airsupply so that the heater plate 71 can heat the wafer 6 to loosen anadhesive holding the dies or IC's 8 to the wafer 6, in use. Athermocouple 79 is connected to the heater plate 71 and operatively tothe PLC 38 with controllers (as described below) so that a temperatureof the heater plate 71 can be controlled with the PLC 38 and controllersvia the heater cartridge 74.

A stepper motor assembly 66 is mounted on the second stage 58. A powerscrew 68 of the stepper motor assembly 66 extends from the stepper motorassembly and engages the wafer support plate assembly 63 in a tangentialmanner. In particular, and as can be seen in FIG. 7, a connector arm 83is fast with, and extends radially from, the heater plate 71. A workingend of the power screw 68 is fast with the connector arm 83 so thatextension and retraction of the power screw 68 causes the wafer supportplate assembly 63 to rotate anti-clockwise and clockwise, respectively,in the embodiment shown in the drawings. The power screw 68 is threadedthrough a screw plate 70 extending from the second stage 58. A spring 72is fastened between the screw plate 70 and the connector arm 83. Thus,the wafer support plate assembly 63 can rotate in one direction underoperation of the power screw 68 and in an opposite direction underspring action. The stepper motor assembly 66 is also connected to thePLC 38 with a suitable controller to control operation of the steppermotor assembly 66. An electrical box 85 facilitates the respectiveelectrical connections of components to the PLC 38, described below andcontroller.

Dice Pick and Lift Head 78

The dice pick and lift head 78 is shown in more detail in FIGS. 8 to 11.The dice pick and lift head 78 includes a mount 89 fastened to thebracket 87 and displaceable along a Z axis (operatively vertically)relative to the bracket 87. The mount 89 and the bracket 87 areconfigured so that displacement of the mount 89 and bracket 87 islinear, the mount 89 defining a linear translation stage 92. A linearencoder 94 provides the necessary positional Z axis feed back values,facilitated by scale tape 103 (FIG. 10) to the PLC 38. Also included isa vertical stepper motor 96 fast with the bracket 87 and engaged withthe mount 89 for displacing the die picker head along the Z axis undercontrol of the PLC 38 using the positional feed back values from thelinear encoder 94.

A pick head plate 97 is attached to the mount 89. The pick head plate 97and the mount 89 are configured so that the pick head plate 97 isdisplaceable along an X axis (operatively horizontally) with respect tothe mount 89. A drive bracket 99 is fast with the mount 89. A pair ofmicrometer drives 98 is fast with the bracket 99 and engage the pickhead plate 97 to displace the pick head plate 97 along the X-axis. Thedrives 98 are connected to the PLC 38 to displace the pick head plate 97under control of the PLC 38. Thus, the pick head plate 97 can beadjusted by the stepper motor 96 and micrometer drives 98 with twodegrees of freedom under control of the PLC 38.

A die picker head (shown in further detail in FIG. 11) is fast with thepick head plate 97, via bracket 101, and has a vacuum body 84 thatdefines a vacuum chamber. The vacuum body 84 has a dice contact surface86 that is configured to touch a dice to be lifted from the wafer 6 onthe vacuum plate 76. The dice contact surface 86 defines a row of vacuumapertures 91 in fluid communication with the vacuum chamber of thevacuum body 84. A pair of sealing strips 93 is positioned on respectivesides of the row of vacuum apertures 91 to facilitate the generation ofa vacuum between a dice to be lifted and the dice contact surface 86.

A vacuum tube 88 is fast with the vacuum body 84 and is connected to avacuum pump, under control of the PLC 38, to generate a vacuum in thechamber when the contact surface 86 touches the dice. A heater cartridge90 is positioned in the vacuum body 84 and is connected to a heated airsupply to heat the surface 86. A thermocouple 95 is connected to thesurface 86 to sense the temperature thereof and report the sensedtemperature to a controller (described in further detail below). Inturn, the controller is configured to control the heated air supply tothe cartridge 90 with a valve so that sufficient heat is generated tofacilitate the separation of dies from the wafer 6 on the vacuum plate76.

Camera and Optical Assembly 82

One embodiment of the camera and optical assembly 82 is shown in FIG.12. In this embodiment, the camera assembly 82 is mounted on a camerabracket 105 fast with the gantry 80 (FIG. 4). As can be seen in FIG. 12,each camera assembly 82 includes a camera 102. A suitable camera is ablack and white IEEE 1394 SXGA+ C-Mount camera with a Megapixel Sony ⅔″type progressive CCD array manufactured by Allied Vision (AVT F-131B).

The camera 102 is mounted on the end of an adapter tube 104 with a 2×lens adapter. A body tube 106 is, in turn, mounted on the adapter tube104. The body tube 106 is in the form of a T-piece with an LED assembly108 with cooling heatsink 110 for required illumination of the wafer 6.The camera assembly 82 also includes a prism 112, arranged at an end ofthe body tube 106. The camera assemblies 82 are configured to generatean image of portions of the wafer 6 for the PLC 38. The cameraassemblies 82 are connected to the touch screen PC 34 so that the imagecan be displayed on a screen of the PC 34 (as described in furtherdetail below). The PC 34 is programmed to identify wafer fiducialmarkings and thus to facilitate positioning of the pick head 78according to a wafer map. This allows software controlling the assembler16 to identify and select respective dies on the wafer 6 using the wafermap.

Wafer Scribe Reader 100

A wafer scribe reader 100 (FIG. 4) is also mounted on the gantry 80. Thewafer scribe reader 100 is configured to use optical characterrecognition to read a wafer identity number on a wafer 6 loaded onto thewafer support plate assembly 63. The wafer identity number is associatedwith the location of a suitable die 8 to be lifted and the controllingsoftware used for lifting the dice from the wafer.

The wafer scribe reader 100 is operatively connected to the PC 34. ThePC 34 is programmed to generate a visible image of the wafer identitynumber. Furthermore, the PC 34 is programmed to generate a graphicaluser interface (GUI). Thus, if the scribe reader 100 has difficulty inreading the wafer identity number, an operator can use the GUI to inputthe wafer identity number manually.

More detail of the wafer scribe reader 100 can be seen in FIG. 13. Thereader 100 includes a housing 107 mounted to the gantry 80 with abracket 109. The housing 107 is configured to support a camera 111 witha video lens 113. The camera 111 is connected to the PC 34 so that thePC 34 can generate the image of the wafer identity number. The housing107 also includes a light source 115 to illuminate the wafer 6 to readthe wafer's identity number, in use.

Shuttle Transfer Apparatus/Die Conveyance Mechanism 20

The shuttle transfer apparatus or die conveyance mechanism 20, inaccordance with an embodiment of the invention, is shown in FIGS. 14 and15. The shuttle transfer assembly 20 is configured to receive dice fromthe pick and lift head 78 and transfer them to the die placementassembly 22, described separately below.

The shuttle transfer apparatus includes a gantry beam 114. The gantrybeam 114 also includes a pair of gantry posts 116 mounted on the opticaltable 26. A shuttle or carriage 118 is mounted on the beam 114 and ismovable along the beam 114. A linear motor 120 is mounted on the beam114 to drive the shuttle 118 to and fro along the beam. The linear motor120 is maunder control of the PLC 38, described below, via a suitablecontroller.

FIG. 15 shows the shuttle or carriage 118 in more detail. The shuttle118 includes a carriage plate 122 fast with a die plate 126. A vacuumplate 124 is fast with the die plate 126 and extends orthogonally fromthe carriage plate 122. The vacuum plate 124 defines a number ofapertures 128 opening operatively upwardly. A vacuum tube 130 is mountedon the shuttle 118 and is connected to an operatively lower portion ofthe vacuum plate 124 and a vacuum pump (not shown) to generate asuitable vacuum when a die is positioned on the vacuum plate 124.

A gel pack 132 is also positioned on the die plate 126. The gel pack 132serves to provide a deposition zone where the pick head 78 is programmedto deposit further dice for sampling purposes. Once deposited, the gelpack 132 can simply be removed from the die plate 126.

The gantry beam 114 is positioned on the support assembly 26 so that theshuttle 118 can be moved from a position in which the vacuum plate 124can receive a die from the pick head 78, once the die has been liftedfrom the wafer. The gantry beam 114 is positioned so that the shuttle118 can be moved to a position in which the die can be lifted from thevacuum plate 124 by the die placement assembly 22 described below.

Die Placement Assembly 22

The die placement assembly 22 (FIG. 16) is configured to receive the diefrom the shuttle 118 and place and bond it in a desired position on theliquid crystal polymer (LCP) carrier or sub-assembly 10 which is clampedin clamp assembly 146, described below.

The die placement assembly 22 includes a frame 138 mounted on supportplatform or the optical table 26 of the assembler 16. In one embodimentof the invention, the frame 138 is of granite. The frame 138 has a bedportion 140 and an upright portion 134, as shown. A spacer 136 ispositioned on the bed portion 140. A cross roller assembly 142 ismounted on the spacer 136. The roller assembly 142 is configured to rollbetween a loading position (shown in FIG. 16), where the carrier 10 isloaded, and a placing position (shown in FIG. 17) where dice are placedonto the carrier 10. A clamp plate 144 is mounted on the cross rollerassembly 142 to be displaceable along an X-axis as indicated by the axesshown in FIG. 16. The carrier clamp or clamp assembly 146 (describedbelow) is mounted on the clamp plate 144 to clamp the LCP carrier 10 inposition for the bonding of the dice.

The die placement assembly 22 includes a carrier loading door 32arranged on the bed portion 140 and mounted to the housing frame 24 ofthe assembler 16 (FIG. 3) via bracket 121 to allow the carrier 10 to beloaded into the clamp 146. A placement head assembly 160 is mounted on amounting plate 162, as shown. The mounting plate 162 is fast with theupright portion 134. The placement head assembly 160 is configured tolift the die from the shuttle 118 and to position it on the carrier 10.The die placement assembly 22 also includes an air heater assembly 164(described below) to facilitate bonding of the dies to the carrier 10,which is held in the clamp 146. The placement head assembly 160 includesa placement head 168 along with placement cameras and related optics166.

Placement Head 168

FIGS. 18 and 19 show a closer view of the placement head 168. Theplacement head 168 includes a placement head mounting block assembly123. The placement head mounting block assembly 123 is fast with theupright portion 134 of the frame 138 through the mounting plate 162.

A Z-axis stage 125 is mounted on the block assembly 123 to beconstrained for displacement along a Z-axis. For that purpose, a Z-axisstepper motor 182 is fast with the block assembly 123 via a bracketassembly 133. The Z-axis stepper motor 182 has a pushrod 135 thatoperatively engages the Z-axis stage 125 to push the Z-axis stage 125along the Z-axis with respect to the block assembly 123. The Z-axisstepper motor 182 is operated under control of the PLC 38 via a suitablecontroller.

A Y-axis stage 127 is mounted on the Z-axis stage 125 to be constrainedfor displacement along a Y-axis (i.e. operatively vertically). For thatpurpose, a Y-axis stepper motor 180 is fast with the Z-axis stage 125via a bracket assembly 137. A push bracket 139 is fast with the Y-axisstage 127 and engages a pushrod 141 of the Y-axis stepper motor 180 viaa compression spring 143. A linear encoder 145 is mounted on the Z-axisstage 125, as shown. Scale tape 147 is fast with the Y-axis stage 127 tobe read by the linear encoder 145 which is connected to the PLC 38 toprovide positional feedback along the Y-axis.

In turn, an X-axis stage 129 is mounted on the Y-axis stage 127 to beconstrained for displacement along an X-axis. For that purpose, anadjustment block 149 is fast with the Y-axis stage 127. A pair of X-axismicrometer drives 176 is fast with the adjustment block 149 and engagesthe X-axis stage 129 to provide adjustment of the X-axis stage 129 withrespect to the Y-axis stage 127 along the X-axis. The micrometer drives176 are connected to the PLC 38, via suitable controllers for control ofthe extent of adjustment of the X-axis stage 129.

A connector block 151 is fast with the X-axis stage 129. In turn, aflexible fixture 172 which can be a T-flex fixture is connected to theconnector block 151. The fixture 172 defines a recess to accommodate adie placer head 170 so that the die placer head 170 extends partiallyfrom the fixture 172. The partial extension of the die placer head 170from the fixture 172 is such that part of the head 170 can be receivedbetween the retaining plates 150 of the clamp 146, described below.

The die placer head 170 is ceramic and defines an aperture 153 in fluidcommunication with a vacuum tube 186 connected to a vacuum pump undercontrol of the PLC 38. The die placer head 170 is shaped and dimensionedto receive a die from the wafer 6 operatively held on the vacuum plate76. At that time, the PLC 38, via suitable controllers, operates toremove the vacuum applied at the vacuum plate 76 and to apply a vacuumat the placer head 170 via the tube 186 so that the dice is held inposition by the head 170.

Air heater tubes 155 are connected to a hot air supply nozzle 600 of aheater valve assembly 602 of the air heater assembly 164 (FIG. 20). Theair heater tubes 155 are connected to the die placer head 170 to heatthe die placer head 170 such that the die can be bonded to thelamination film 12 on the carrier 10.

An angular motor 161 is also mounted through the X-axis stage 129 and isfast with the connector block 151. Actuation of the angular motor 161 bythe PLC 38, via a suitable controller, causes angular pivoting of thedice placer 170 about the Y-axis. Also provided is angular movementspring 131 fast with the X-axis stage 129, as shown, to bias the angularmovement of the placer 170 against the urging of the motor 161 to ensuresmooth operation thereof.

Thus, the PLC 38 can be programmed so that when the insert 152 of theclamp 146 is correctly positioned in the clamp 146, the head 170 can bepositioned to bear against the lamination film 12 and heated to bond thedice to the lamination film 12.

Air Heater Assembly 164

The air heater assembly 164 is mounted on the cross roller assembly 142to direct heated air onto the carrier 10 held in the clamp 146. Thisserves to facilitate bonding of the die to the thermoset lamina film 12on the carrier 10. The air heater assembly 164 is shown in more detailin FIG. 20. The air heater assembly 164 includes a heater mount plate604 (FIG. 20). An air process heater 606 is mounted on the mount plate604. The air process heater 606 receives an electrical power supply at608 from an electrical box 614 (FIG. 16). The air process heater 606 iselongate with a cold air supply 610 at one end, as shown.

The heater valve assembly 602 is mounted on the air process heater 606at an opposite end from the cold air supply 610. A thermocouple 612 ispositioned in the heater valve assembly 602 to provide the PLC 38 with asignal to facilitate control of the heater valve assembly 602 via theelectrical box 614 (FIG. 16). A hot air supply nozzle 600 and a hot airdivert tube 616 are connected to the heater valve assembly 602.

A pneumatic actuator 618 is mounted on the heater mount plate 604 tocontrol operation of the heater valve assembly 602 via a connecting rod620. The pneumatic actuator 618 is operatively connected to the PLC 38via a suitable controller, as described below, to control the egress ofhot air from the heater valve assembly 602.

Placement Camera and Optics Assemblies 166

The placement camera and optics assemblies 166 enable the PC 34 toposition the head 170 correctly over the carrier 10 prior to placing thedice.

The camera and optics assemblies 166 are mounted on a camera and opticsassembly bracket 622 (FIG. 16) which, in turn, is fast with the mountingplate 162 on the upright portion 134 of granite frame 138. The cameraand optics assemblies 166 are similar to the wafer camera and optics 82shown in FIG. 12 and described above. It follows that the same referencenumerals are used when referring to the components of the assemblies166.

Each camera 102 is connected to the touch panel PC 34 so that an imageof part of the clamp 146 and the carrier 10 can be displayed to anoperator. The touch panel PC 34 is programmed to communicate with thePLC 38 as soon as the PC 34 identifies the ink outlets 14 in thelamination film. Identification of the ink outlets 14 permits the PC 34to control the PLC 38 such that the carrier fiducials 15 (FIG. 2) andink outlets 14 serve as placement fiducials. Thus, the PC 34 is able todetermine a correct placement for dies to be bonded to the laminationfilm 12 of the carrier 10, described above.

Each die 8 typically has fiducials at each end which can be imaged bythe cameras 102. Since a pair of cameras 102 is used to “see” thefiducials, the PC 34 is able to determine co-ordinates of the fiducialsof respective dice relative to each other. This allows adjustment of thehead 170 to ensure that respective dice are placed on the carrier 10 inalignment with each other.

Clamp Assembly

The clamp assembly 146 is shown in more detail in FIGS. 21 and 22. Thesubstrate clamp 146 is pneumatically operated. It includes an elongateclamp body 148 in which the carrier 10 is received. In particular, aninsert 152 can be received in the clamp body 148. The carrier 10 ismounted on the insert 152 with location dowels 157 to ensure that theinsert 152 is correctly positioned.

The clamp assembly 146 includes an insert stop 156 at one end of thebody 148. A proximity switch 159 is mounted on the stop 156 to generatea signal, receivable by the PLC 38, when the insert 152 reaches the stop156.

The clamp assembly 146 includes a pair of elongate retaining plates 150mounted on the body 148 and defining an access gap 624 of sufficientwidth to permit positioning of the printhead integrated circuits 8 onthe lamination film 12 of the carrier 10.

A diaphragm 625 is positioned in the body 148 and is displaceabletowards and away from the retaining plates 150 with air supplied via airconduits 626. The diaphragm 625 and insert 152 are configured so that,when the insert 152 is received in the body 148, the diaphragm 625 canbe activated to urge the carrier 10 against the retaining plates 150with the gap 624 providing the necessary space for the placement of theintegrated circuits. Thus, under control of the PLC 38, when the insert152 is inserted into the body 148, an air supply can be provided, via apneumatic fitting 158 to the diaphragm 155 to urge the carrier 10against the pneumatic plates 150 so that the carrier 10 is retained inposition during placement of the integrated circuits 8. A handle or knob154 is fast with the insert 152 to facilitate manipulation of thecarrier 10 into position between the clamp plates 150 prior to clampingof the carrier 10.

Processes

Generally, the process carried out by the assembler 16 can be summarizedas follows:

-   -   The carrier 10, mounted on the insert 152, is scanned for a        serial number and then loaded into the clamp 146, as described        above, such that an attachment surface defined by the lamination        film 12 is substantially flat.    -   The carrier 10 is moved, together with the carrier 10 to where        the camera and optics assemblies 166 are, together with the PC        34, used to locate fiducials on the carrier surface to provide a        reference for a first die 8 to be placed on the carrier surface.    -   A wafer 6 is scanned and loaded onto the vacuum and heater plate        assembly 76. The assembler 16 makes use of an input instruction        file or wafer map associated with the wafer 6 to determine the        actual dice, and their positions, to be attached to the        lamination film 12 on the carrier 10.    -   Once the die 8 is released from the wafer 6, it is transferred        to a die placement location, aligned and attached to the        lamination film. How this is done is described above with        reference to the relevant components.    -   Once the die 8 is aligned, it is lowered into contact with the        lamination film 12 and a set pressure is applied.    -   Once in contact with the lamination film 12, the die 8 is heated        for a predetermined duration to attach the die 8 to the        lamination film, which is typically a thermoset film.

These steps are performed by various components controlled by the PLC 38under supervision of the PC 34 and with various controllers.

In order to describe how the various components, described above, carryout these steps, it is necessary to refer initially to a high level dataflow diagram as shown in FIG. 23. The diagram shown in FIG. 23 shows amethod or process and a system, in accordance with one embodiment of theinvention, for controlling operation of the printhead assembly machineor assembler 16 for assembling printhead integrated circuits on acarrier.

In this embodiment, such a system is generally indicated by referencenumeral 630. The system 630 includes a Manufacturing Execution System(MES) server 632 and an industrial computer 634 running printheadassembly machine (PAM) application software for the assembler 16. TheMES server 632 and industrial computer 634 are collectively referred toas a remote monitoring system.

In this embodiment, the MES server 632 provides the PLC 38 of theassembler 16 with the wafer map and operating instructions, mentionedabove. The industrial computer 634 (equivalent to the PC 34) receivesdata via an Ethernet module of the PLC 38. This data typically includespositions or axis coordinates of the respective actuators or drivesdescribed above, task responses, process variables, or the like. Inaddition, the PLC 38 also sends the industrial computer 634 statemachine tasks to perform, as shown.

The data sent by the PLC 38 to the computer 634 can includes number ofdice consumed from the wafer 6, placement order of the dice, the scannedidentity number of each wafer, positions of die and carrier fiducials,start and stop cycle times, operator identity, carrier barcodes, statusof parts used, etc.

The industrial computer 634 and the MES server 632 exchange instructionsand data relating to the operation of the assembler 16, typically viaTCP-IP. The MES server 632, in turn, supplies the PLC 38 withinformation regarding the wafer map indicating which dice on the loadedwafer is to be mounted on which carrier, process parameters, etc.

As indicated, the PLC 38 is configured, via suitable softwareinstructions, to define a number of state machines necessary to controloperation of the assembler 16. This PLC 38 defines a place state machine636, controlling operation of the die placement assembly 22, a transferstate machine 638, controlling the shuttle transfer assembly 20, and apick state machine 640 controlling the die picking assembly 18. The PLC38 also defines a motion control state machine array 644 responsible forcontrol of the relevant actuators and drives, described above withrelation to the different components and collectively indicated at 637.A supervisory state machine 642 is also shown which is responsible forsafety and supervision of the operation of the assembler 16.

FIG. 24 shows a flow diagram of a global overview for a method orprocess, in accordance with one embodiment of the invention, performedby the various components, described above, under control of the PC 34,the PLC 38, an operator and/or the remote monitoring system or RMS(indicated at 408) in controlling the assembler 16. As mentioned above,the RMS 408 includes the MES 632 and the industrial computer 634. It isto be appreciated that some of the steps are performed automatically bythe PC 34, PLC 38 and RMS 408, whilst others require input from anoperator.

It is to be appreciated that reference to a reference numeralrepresenting a particular method step refers to a respective blockindicated by such reference numeral in the accompanying drawings. Assuch, the method included in the invention is not limited or constrainedto particular method steps referred to in this manner. A skilled personwill understand that further methods are possible under this inventionwhich might exclude some of these steps or include additional steps.

General steps for the assembler 16 having the die picking assembly 18,the die conveyance mechanism 20 and the die placement assembly 20 areshown. The remote monitoring system 408 is arranged in signalcommunication with the PLC 38, as described above, and allows remotemonitoring and control of an operational status of the assembler 16. TheRMS 408 is also able to keep track of carriers and wafers, as well aswhich dies are placed on which carriers. The RMS plays an integral rolein quality and assurance control for assembly of the carrier 10.

As shown, the process includes a wafer loading phase 398, a carrierloading phase 412, a die attach stage 424, and a processed carrierremoval stage 436.

The wafer loading stage 398 features the steps of removing the waferfrom a clean cassette wherein the wafers are stored (block 400), loadingthe wafer into the assembler 16 (block 402), and the PLC 38 reading thewafers barcode (block 404). In the embodiment shown, the wafer mappingscheme is retrieved by the PLC 38 from the remote monitoring system 408(block 406), as described above. This wafer mapping scheme typicallyprovides a location and picking order of the ICs on the wafer 6. Thewafer 6 is then placed onto the wafer heating and vacuum plate 76.

The carrier loading phase 412 features the steps of removing the carrier10 from a tray (block 414) whereafter the barcode of the carrier 10 isscanned by the PLC 38 and sent to the remote monitoring system 408. Inthe embodiment shown, the carrier 10 consists of a liquid crystalpolymer (LCP) substrate, as indicated in some of the blocks. The remotemonitoring system 408 checks whether or not the carrier has clearedquality control tests previously performed thereon, before the PLC isinstructed to assemble the dies thereon. If the carrier has cleared suchtests (block 418) and is of sufficient quality, the operator removes aprotective liner (block 420) covering the lamina 14 and loads thecarrier into the assembler 16 (block 422).

The die attach process 424 follows with the assembler initializing(block 426), and scanning the wafer to locate the dies according to thewafer substrate mapping scheme from the remote monitoring system 408(block 428). The dies are then picked from the wafer (block 430) andtransported to the placement assembly 22 where they are bonded to thecarrier (block 432). The picking and placement steps are repeated untilthe carrier includes the required number of dies (block 434) specifiedby the wafer map.

The processed carrier removal stage 436 includes a scan of the completedcarrier with ICs which define a printhead (block 438) and sending thequality report to the remote monitoring system at block 440. The carrier10 is then moved to the unloading position (block 442) where theoperator can remove it from the assembler 16 and inspect it visually at444. The completed carrier 10 with printhead is then placed into a trayat block 446.

FIG. 25 shows specific steps performed during operation of the diepicking assembly 18 in picking the dies from the wafer 6. The methodtypically commences with an operator loading a wafer 6 into theassembler 16, indicated at block 200. The wafer 6 is positioned on thewafer positioning assembly 48, described above.

The assembler 16 initializes (block 202) and the scribe reader 100 isused, under control of the PLC 38, to scan the wafer barcode at block204. The PLC 38 is configured so that an unsuccessful scan, decided atdecision block 206, of the barcode causes the PLC 38 to unlock a waferloading door (block 208) of the assembler 16 so that the operator canremove and/or reposition the wafer on the assembly 48 (block 210). ThePC 34 is configured to control the wafer cameras and optics 82 to checkfor a starting point or datum marked on the wafer (block 212), whichserves as reference point for the wafer substrate mapping scheme used bythe PLC 38 to locate the respective dies on the wafer 6.

Once the camera and optics 82 have been focused at 214, the PLC 38checks the die picker 81 for position of the stage 92 and the drives 98along with the heater 90 (block 216). Should the die picker 81 fail thecheck, the assembler 16 re-initializes and might issue a warning to theoperator. If the die picker 81 passes the check, it is raised (block218) and moved to a reference point indicated by the mapping scheme(block 220). The PLC 38 uses the camera and optics 82 to find thereference point on the wafer 6 (block 222). If the PLC is unable tolocate the reference point, the wafer loading door is unlocked allowingaccess to the wafer 6.

The optics 82 checks the wafer (block 224) and coordinates for a die tobe picked is requested by the PLC from the mapping scheme (block 226).Failure of any of these two steps leads to unlocking of the wafer accessdoor, as shown. If the coordinates are provided, the die picker 81 ismoved to the correct position (block 228), else the coordinates arerequested again. Once the die picker 81 is in position, the pick surface86 is lowered (block 230) and contacted with the die and the wafer isheated with the heater 90 (block 232) to loosen an adhesive holding thedie to the wafer 6. The die is then gripped by a vacuum establishedthrough the pick surface 86 (block 234), as described above, and the diepicker is raised (block 238) to remove the die from the wafer 6.

The die picking assembly 18 then waits for the die conveyance mechanism20 (block 240) to get into position, whereafter it lowers the die ontothe shuttle 118 (block 242) and releases the die by removing the vacuum(block 244). The die picker is raised again (block 246) and the processis repeated, as shown, if additional dies must be picked from the wafer(decision block 248). If the mapping scheme does not require furtherdies to be picked, the die picker is returned to a waiting position fora new wafer to be loaded into the assembler 16 (block 250).

FIG. 26 shows one embodiment of a method performed by the die conveyancemechanism 20. Similar to the die picking assembly above, the processcommences with initialization of the mechanism 20 (block 260). Theshuttle 118 waits for the die picker 81 (block 262) until the pickermoves into position over the shuttle 118 (block 264). Once the diepicker 81 is in position, the vacuum plate 124 on the shuttle 118receives the dice and grips the dice by establishing a vacuum (block266). The shuttle 118 waits for the pick head to raise (block 268)whereafter it transfers along the gantry beam 114 to the die placementassembly 22 (block 270).

The placement head assembly 160 includes the dice placer 170. Theshuttle 118 waits for the placer 170 to move into position (blocks 272and 274), whereafter the vacuum plate releases the gripped dice (block276) and remains in place (block 278) so that the picker 170 can pick itup. When the picker 170 has removed the dice, the shuttle moves back tothe die picking assembly 18 to repeat the process (block 280).

FIG. 27 generally shows one embodiment of method steps for the tasksperformed by the die placement assembly 22. The process also starts withthe assembly 22 initializing (block 300) whereafter the carrier 10 isloaded into the clamp 146 (block 302) via the carrier loading door 119and clamped (block 304) in clamp 146. The carrier 10 is then moved intoa reference position by the cross roller stage 142 at block 306. Theplacement cameras and optics 166 scans the carrier 10 for the fiducialindicators 15 for aligning the dies thereon. If the fiducials are notfound (decision block 308), the stage 142 moves the carrier 10 to anunload position (block 312).

If the fiducials are found, the stage 142 moves the carrier 10 into aplacement position (block 310) where the placement assembly 160 canplace the dies onto the carrier 10. The placement head 168 waits for theshuttle 118 to deliver the die picked from the wafer, described above(block 314). Once the shuttle is in place, the placement head 168 islowered (block 316). If the dice is correctly positioned (decision block318), the dice placer 170 is lowered (block 320) to grip the dice (block322). Otherwise, the placement assembly 160 is moved back to theplacement position.

Once the dice has been gripped, the dice placer 170 is raised (block324) and the transfer shuttle 118 is checked for clean pick-up (block326) and moved away back to the die picking assembly 18 (block 328). Thedice placer is moved to a place position over the carrier 10 (block 330)and the PC 34, via the camera and optics 160, aligns the gripped dicewith the carrier (block 332). The die placer head 170 is lowered at 336.The die placer head 170 then places the dice onto the carrier 10 throughgap 159 of clamp 146. The air heater assembly 164 the dice and carrierto secure the dice to the thermoset lamina 14 (block 338), whereafterthe dice is allowed to cool (block 340).

The placement camera and optics 166 then allow the PC 34 to check theplacement of the dice on the carrier (block 342), before the placementhead 168 is raised (block 344) and moved for the next dice placement(block 346).

Once the head 168 is moved out of the way (block 346), the PLC 38 cancheck the final position of the dice (block 348) and move the carrier 10to an unloading position (block 350), where the operator can unclamp thecarrier (block 352) and remove it from the housing 24 of the assembler16, prior to loading a further carrier (block 354).

Operator Interface

FIG. 28 shows, schematically, a left-hand portion of the assembler 16 ofFIG. 3, showing the operator interface in more detail. The interfaceincludes the touch panel PC 34 and the control button console 36. Alsoshown is a warning beacon 464 (numeral 35 in FIG. 3) and emergency stopbuttons 460 and 462. Button 460 is an operator emergency stop button,with button 462 being a maintenance emergency stop button. The carrierloading door 119 is positioned in the front panel 461 of the enclosure24 of the assembler 16, as shown. The granite frame 138 of the dieplacement assembly 22 can be seen through the loading door 119, alongwith clamp plate 144 and clamp 146.

Electrical Components

FIG. 29 shows the electrical enclosure 44 at the rear of the assembler16 (FIG. 3) in an open position. The control system of the assemblerincludes the PLC 38, which is a Mitsubishi FX3U-64M PLC unit 645 havingexpansion blocks in the form of a FX2N-2LC temperature control block 646(FIG. 33) in the form of modules, a FX3U-ENET Ethernet interface module647, a FX0N-3A analog I/O special function block or module 648, and aFX2N-32CAN controller area network (CAN) serial bus interface module649.

The PLC 38 is connected to the PC 34 with an Ethernet switch 650 asshown in FIG. 32. The PLC 38 receives programmed instructions from thePC 34 such that the PLC 38 can control operation of the die pickingassembly 18, the transfer mechanism 20 and the die placement assembly22.

Lighting controllers 470 (FIG. 29) are included to control the LEDadaptors 108 of the cameras and optics 82 and 166. The controllers 470are Gardasoft PP610 lighting controllers. Also included are the vacuumpumps 472 for providing the various required vacuums for securing thewafer and dies in the relevant components of the assembly 16, asdescribed above. The vacuum pumps 472 are Busch dry-running rotary vanetype pumps.

It is to be appreciated that the respective components are connected viaelectrical and/or pneumatic connections housed in trunking 471. Rail 473provides mounting locations for the different components housed inenclosure 44. As such, the physical connections between the componentsare diagrammatically indicated, as the skilled person will understandthe required connections.

Motor axis controllers collectively indicated by numeral 474 areconnected to the PLC 38 to facilitate control of the different motorsand drives of the components of the assembler 16. A more detaileddescription of this motor control is provided below.

A Power supply 476 is configured for providing a 160 Volt DC supply tooperate the vacuum pumps 472. Power supplies 496 are configured forproviding 5, 9, 15 and 24 Volt power supplies to relays and motorcontactors of the assembly.

Relays 478 and fuses 480 provides connection to and protection for theelectrical components powered by power supply 476, with relays 492 andfuses 494 providing connection to and protection for components poweredby supply 496.

Relays 482 provide a connection for the heater elements of the assembler16. It is to be appreciated that the different relays allow the PLC 38to activate and deactivate the respective components. Also shown is a 48Volt power supply 484 and Ethernet switch 486 (shown as 650 in FIG. 32).Circuit breakers 488 provide overcurrent protection for the components.Motor contactors 490 are connected to the controllers 474 to allow thePLC 38 to control various motors of the assembler. Safety mutingcontroller 498 and door switch controller 500 provide safety bydeactivating the assembler if a door, such as carrier loading door 119,is opened whilst the assembler 16 is active. Pneumatic enclosure 501forms part of the pneumatic enclosure 46 (FIG. 3) of the assembler 16.

Motor Control

FIG. 31 provides a schematic overview of the motor control tasksperformed by the PLC 38. As described above, the PLC receives the wafermapping scheme and related operational parameters from the remotemonitoring system having the MES server 632 and the industrial computer634 (or PC 34), described above. The different motors and drivesdescribed above are controlled by the PLC 38 through the respectivemotor axis controllers collectively indicated by reference numeral 474.

As described above, the placement head 168 includes actuators 161, 176,180 and 182. The inventor has found that an Akribis linear motor 180with an Elmo driver 474.1 is suitable for this application. Similarly, aZaber 2 phase stepper motor 176 with a Copley driver 474.2 is used,along with a Zaber 2 phase stepper motor 182 with a Copley driver 474.4.The angular motor 161 is also a Zaber 2 phase stepper motor with aCopley driver 474.3.

The die conveyance mechanism or shuttle transfer mechanism 20 includesthe linear motor 120, which is an Akribis AC servo motor with an Elmodriver 474.5.

Similarly, the die picking assembly 18 includes the actuators 66, 96, 62and 60, as described above. The wafer positioning assembly 48 has thetwo stages both actuated by Nanomotion piezo caterpillar motors 60 and62 having a Nanomotion drivers 474.8. The wafer rotate motor 66 is aZaber 2 phase stepper motor with a Copley driver 474.6, and the pickhead vertical motor 96 is a Zaber 2 phase stepper motor with a Copleydriver 474.7. It is to be appreciated that all the drivers 474 providethe PLC 38 with positional feedback information for the drives.

Pneumatic Enclosure 46

FIG. 30 shows the pneumatic enclosure 501 (part of enclosure 46 in FIG.3) of the assembler 16 in an open position showing the pneumaticcomponents used by this embodiment of the assembler. An SMC AF40 seriesair filter 504 is used immediately after main shut-off valve 502 tofilter impurities from the air supply. The filter 504 has a float typeauto-drain system. The assembler 16 also includes an SMC AFM series mistseparator 530 to filter particles from the supply, followed by an SMCAFD series micro-mist separator 532 to filter smaller particles whichmight pass through separator 530. An SMC AME series mist separator 514is included to absorb fine oil particles from the pneumatic system ofthe assembler 16.

Inline gas filters 518 are included from the SMC SF series to remove anyremaining particles from the pneumatic supply. The filters 518 include aPTFE membrane. High purity valves 520 are included for operating thevarious pneumatic components, and a membrane air dryer 534 to removemoisture. Pressure regulators 506, 510, 512 and 526 are used to regulatepressure in the various pneumatic systems. Isolation valves 502 and 528are used to isolate the respective pneumatic circuits from each other.Pressure switches 508 are used to provide pressure readings for the diepicker, transfer shuttle and die placement pneumatic systems. Solenoidvalves 524 are used to control the pneumatic system with the PLC 38,with flow sensors 516 reporting flow information to the PLC 38.

Safety

The controller or PLC 38 includes a number of safety features forprotecting the assembler 16, carrier 10 and wafer 6 from damage, as wellas an operator from harm. As such, the PLC 38 is configured to monitoran operational status of the assembler 16 by means of the variouscomponents described above. If a potentially hazardous situation isdetected, the PLC 38 is configured to deactivate the assembler 16. Ahazardous situation can include unexpected electrical fluctuations,pressure fluctuations, unpredictable operational parameters, the PLC 38sensing the presence of a foreign object proximate moving parts of theassembler 16, or the like.

FIGS. 32 to 37 show circuit diagrams of interconnections between some ofthe electrical components described above. It is to be appreciated thatthe circuit diagrams are described in overview with only some of theconnections indicated. The circuit diagrams are meant to assist theskilled person in interpreting the interconnections between thecomponents, and not to provide an exhaustive circuit description. In thecircuit diagrams, like reference numerals indicate like connectionsunless otherwise indicated.

A main safety relay 668 (indicated by reference numeral 492 in FIG. 29)is shown in FIG. 35. The relay 668 is an Omron G9SA-321-T safety relayunit and is connected to emergency stop buttons 460 and 462, as shown.The relay 668 also has connections to the PLC 38 at 666, as shown.

FIG. 36 shows further component connections of a safety system of theassembler 16. Door muting controller 498 is connected to door switchcontrollers 500, as shown, and to door safety switch 670. Door switchcontrollers 500 are arranged in communication with magnetic doorsswitches 672, 674 and 676, as shown. If any of the assembler's doorpanels are opened during operation, the safety system automaticallydeactivates the assembler to prevent injury and/or damage.

Computer Control

FIG. 32 shows a control diagram illustrating one role of the PC 34 incontrolling optical components of the assembler 16. As can be seen, thepick cameras 111 and the place cameras 116 are directly connected to thePC 34 with Firewire connections 652. As set out above, the PC 34 isconfigured to control operation of the cameras 111, 116.

The wafer scribe reader 100 is also connected to the PC 34 with asuitable USB connection, as shown. The PC 34 has an RS232 communicationsport 654 with which it communicates with a pair of LED lightingcontrollers 470 (FIG. 33).

FIG. 33 shows the lighting controllers 470 in more detail. The lightingcontroller 470.1 is configured to control LEDs 660 for the pick head 78to facilitate detection by the cameras 111. The controller 470.1 is alsoconfigured to control LEDs 662 for the place head 170 to facilitatedetection by the cameras 166. The lighting controller 470.2 isconfigured to control LEDs 664 for side lighting for the place head 170.

FIG. 32 also shows the connection between the PC 34 and the Ethernetswitch 486. The switch 486 is connected to the PLC 38 at 664 and to anEthernet network at 666.

FIG. 34 shows the control system of the assembler which includes the PLC38, which is a Mitsubishi FX3U-64M PLC unit 645 having expansion blocksin the form of a FX2N-2LC temperature control block 646 in the form ofmodules, a FX3U-ENET Ethernet interface module 647, a FX0N-3A analog I/Ospecial function block or module 648, and a FX2N-32CAN controller areanetwork (CAN) serial bus interface module 649.

FIG. 37 shows interconnections between the temperature control modules646 of the PLC 38 and respective heater cartridges and thermocouplesused to regulate and control the heating of the wafer 6, the air heaterassembly 164, and the heater cartridge 90 of lift head 78.

As shown, one temperature module 646 is responsible for controlling theheater cartridge 684 for the dice pick head 78 via relay 682 andthermocouple 686. Similarly, a temperature cartridge 690 of the wafersupport 63 is heated via relay 680 and thermocouple 688 providingtemperature feedback. The second temperature module 646 is responsiblefor control of heater cartridge 698 of the dice placing head via relay692 and thermocouple 694.

The skilled person will appreciate that the embodiments described abovemay include various alterations which still fall within the scope of theinvention.

1. A dice placement assembly for placing a plurality of inkjet printheaddice on a printhead carrier so as to form a pagewidth inkjet printhead,said assembly comprising: a support platform with a clamp mechanismclamping the printhead carrier, said printhead carrier having aplurality of discrete tortuous ink paths for ducting ink to theprinthead dice, each of said ink paths terminating at a respectivefiducial aperture; at least one camera operatively directed at theplatform to detect the fiducial apertures on the printhead carrier; asupply of the printhead dice, each printhead dice having a fluid inletfor connection to a corresponding fiducial aperture of the printheadcarrier; a placement device comprising: a vacuum mechanism to retrieve aprinthead die individually from the supply of printhead dice; actuatorsto align each individually picked printhead die with the printheadcarrier and to place the printhead die directly in contact with theprinthead carrier once aligned; and a heater to heat the printhead dieprior to placement on the printhead carrier; and a controlleroperatively controlling the clamp mechanism, the camera and theplacement device, configured to facilitate accurate placement of theprinthead dice on the printhead carrier such that a predetermined numberof printhead die are sequentially positioned across the printheadcarrier to form said pagewidth inkjet printhead.
 2. The placementassembly of claim 1, wherein the camera includes a camera module linkedto a prism by means of an adapter tube to focus said camera on theprinthead carrier.
 3. The placement assembly of claim 1, wherein theactuators of the placement device includes three stepper motors eachseparately responsible for vertical, horizontal and angular alignment ofthe printhead dice with the printhead carrier, respectively.
 4. Theplacement assembly of claim 1, wherein the actuators of the placementdevice includes a linear translation stage for moving the printhead dicein a vertical direction for placing the printhead dice onto theprinthead carrier.
 5. The placement assembly of claim 1, wherein theplacement device includes a heated air blower configured to directheated air at the dice prior to the placement device placing theprinthead dice onto the printhead carrier.
 6. The placement assembly ofclaim 1, wherein the placement device includes a lighting arrangementfor illuminating the printhead carrier to assist the camera in detectingthe alignment fiducials.
 7. The placement assembly of claim 1, whereinthe support platform includes a pneumatically operated self-levelingplatform controlled by the controller.
 8. A method of placing aplurality of inkjet printhead dice on a printhead carrier so as to forma pagewidth inkjet printhead, said method comprising the steps of:clamping the printhead carrier using a clamping mechanism, saidprinthead carrier having a plurality of discrete tortuous ink paths forducting ink to the printhead dice, each of said ink paths terminating ata respective fiducial aperture; detecting the fiducial apertures on theprinthead carrier using at least one camera; providing a supply of theprinthead dice, each printhead dice having a fluid inlet for connectionto a corresponding fiducial aperture of the printhead carrier; placingthe printhead dice on the printhead carrier, said placing comprising thesteps of: picking an individual printhead die from the supply ofprinthead dice using a vacuum mechanism; aligning each individuallypicked printhead die with the printhead carrier and placing theprinthead die directly in contact with the printhead carrier oncealigned; and heating the printhead die prior to placement on theprinthead carrier; and repeating said steps until a predetermined numberof printhead dice are sequentially positioned across the printheadcarrier to form said pagewidth inkjet printhead.